Device for detecting impacts on an aeronautic propeller

ABSTRACT

A device for detecting and recording impacts along several axes on an aeronautic propeller assembly, which has a hub and two blades, is provided. The device has a plurality of accelerometers integrated with the hub of the aeronautic propeller assembly and arranged at the respective root end of a plurality of blades, and an electronic module for recording during the life span any occurrence of shocks at various predetermined levels.

Device for detecting impacts on an aeronautic propeller assembly The present invention concerns the detection of impacts on an aeronautic propeller assembly made up of a hub and blades.

The object of the invention is to propose a device that permits knowing, over the service life of a blade, during planned maintenance or in case of an incident, whether the blade had been subjected to impacts beyond levels normally encountered in normal use. The invention proposes a reliable and autonomous means for detecting and recording any abnormal impact during use, which means can be consulted during maintenance operations.

In a parallel patent application, filed under the number PCT/FR 02 01727 and whose contents are integrated into the present application by reference, the Applicant has already proposed a device for detecting and recording impacts along several axes of an aeronautic propeller blade, characterized in that it comprises an accelerometer integrated at the center of an aeronautic propeller blade and an electronic module to record any occurrence of impact different from predetermined levels during its service life. The device comprises an accelerometer with at least two axes integrated at the top of the blade equilibration device and it records impacts in two planes perpendicular to the axis of the blade. The accelerometer signals can be transmitted remotely to an electronic module situated in any location whatever and this electronic module makes the recordings, but, advantageously, the electronic module (and all its attached elements such as power supply, which also serves the accelerometer) is also integrated into the root of the blade, so that the device is completely autonomous and integrated with the blade. Thus, according to this parallel application, so as to monitor, count and record abnormal impacts, an accelerometer with 2 or 3 axes connected to an autonomous electronic module supplying the accelerometer is integrated, recovering data sent back from the accelerometer, in order to compare these data to predetermined levels, storing occurrences beyond the predetermined levels in memory and integrating a memory reading device, either by direct connection, or by UHF remote transmission.

The preceding invention therefore proposes integrating, at the root of the blade, a completely autonomous system for measuring and recording impacts beyond predefined thresholds, so as to monitor, by interrogation of the system, the number of cases encountered in use for the different predefined thresholds.

The object of the present invention is to propose a variant of the preceding invention.

The invention achieves its object by means of a device for detecting and recording impacts along several axes on an aeronautic propeller assembly made up of a hub and blades, characterized in that it comprises a plurality of accelerometers, which are integrated at the hub of the aeronautic propeller assembly and are positioned at the respective root of a plurality of blades, as well as an electronic module to record, during its service life, any occurrence of impacts at various predetermined levels. Each accelerometer with one or two axes is integrated at the level of the hub/blade connection in the plane that is most suitable as a function of the number of axes, recording impacts during functioning.

Advantageously, the device comprises at least one accelerometer with at least 2 axes integrated at the hub and positioned in the plane of each blade. In the case where the number of blades is even in number, it is useful to install only one accelerometer in the same plane for two blades.

The invention will be better understood and other advantages and characteristics will be demonstrated upon reading the following description referring to the attached drawings in which:

FIG. 1 is a sectional view of a propeller hub and a propeller blade root showing the implantation of the sensor/electronic module system,

FIGS. 2 and 3 are surface views of a propeller showing the implantation of the sensors relative to the blades, respectively, which are even and uneven in number,

FIG. 4 is a variant of FIG. 2 showing a simplified implantation in the case of an even number of blades,

FIG. 5 is a view of a variant of FIG. 1 at the level of the reading means for the electronic module,

FIG. 6 is a diagram of the electronic module.

FIGS. 1 and 5 show one example of implantation of the impact sensor (accelerometer) and the electronic module relative to a root 10 of an aeronautic propeller blade 14. The device of the invention comprises, on one hand, an accelerometer 1 with 2 or 3 axes, set in hub 13 in the neighborhood of root 10 and, on the other hand, an autonomous electronic module 2, also positioned in hub 13 and connected to the accelerometer 1 via connection wires 3.

FIG. 1 shows an electronic module 2 integrating a connector 4 for the function of reading the memories of module 2 by direct connection; the major appeal of this version is its autonomy associated with the very low [energy] consumption of the electronic module.

According to FIGS. 2 and 3, sensors 1, associated with a single electronic module 2, are equal in number to blades 14 and are situated in the plane of each blade. However, in the case of an even number of blades, as in the case of FIG. 2, the blades are placed opposite one another two by two, and a savings can be made by positioning a sensor in the common plane of two opposite blades; this is shown in FIG. 4 where there are only 3 sensors 1 for 6 blades 14.

FIG. 5 shows an electronic module integrating an infrared linking device 6 permitting very simple remote reading, eliminating the disadvantages of a physical connection.

FIG. 6 diagrams the electronic module 2 comprising a power supply 20 by means of a lithium-type battery, for example, a circuit 21 assuring the processing of the accelerometer signals, processing the data or feedback of the data via an analog/digital converter 22, a microprocessor 23 and a permanent memory 24 permitting storing in the form of a table, the number of occurrences of impacts for each axis of accelerometers 1 for each predefined level. In order to equip the embodiment of FIG. 5, module 2 also comprises a transmission unit 25 to communicate with a transmitter Tx or a receiver Rx. 

1-5. (canceled)
 6. A device for detecting and recording impacts along several axes of an aeronautic propeller assembly having a hub and a plurality of blades with each blade having a root, the device comprising: a plurality of accelerometers integrated at the hub, each of said plurality of accelerometers being positioned at one of the roots of the plurality of blades; and an electronic module to record, during a service life of the aeronautic propeller assembly, any occurrence of the impacts at predetermined levels.
 7. The device of claim 6, wherein said electronic module is integrated into the hub.
 8. The device of claim 6, wherein said plurality of accelerometers are directly connected to said electronic module for reading the recording.
 9. The device of claim 6, wherein said plurality of accelerometers are remotely connected to said electronic module for reading the recording, and wherein said remote connection uses infrared signals.
 10. The device of claim 6, wherein at least one accelerometer of said plurality of accelerometers has at least two axes integrated in the hub and positioned in a plane of the plurality of blades.
 11. The device of claim 10, wherein said plurality of accelerometers are directly connected to said electronic module for reading the recording.
 12. The device of claim 10, wherein said plurality of accelerometers are remotely connected with said electronic module for reading the recording, and wherein said remote connection uses infrared signals.
 13. The device of claim 10, further comprising a transmitter or a receiver, wherein said electronic module comprises a transmission unit capable of communicating with said transmitter or said receiver.
 14. The device of claim 10, wherein said electronic module is integrated into the hub.
 15. The device of claim 14, wherein said plurality of accelerometers are directly connected to said electronic module for reading the recording.
 16. The device of claim 14, wherein said plurality of accelerometers are remotely connected with said electronic module for reading the recording, and wherein said remote connection uses infrared signals.
 17. A device for detecting and recording impacts along several axes of an aeronautic propeller assembly having a hub and a plurality of blades with each blade having a root, the device comprising: a plurality of accelerometers integrated at the hub, each of said plurality of accelerometers being positioned at one of the roots of the plurality of blades; and an electronic module to record, during a service life of the aeronautic propeller assembly, any occurrence of the impacts at predetermined levels, wherein said electronic module has a power supply, a circuit for the processing of accelerometer signals, an analog/digital converter, a microprocessor and a memory for storing a number of the occurrences of the impacts.
 18. The device of claim 17, wherein at least one accelerometer of said plurality of accelerometers has at least two axes integrated in the hub and positioned in a plane of the plurality of blades.
 19. The device of claim 17, wherein said electronic module is integrated into the hub.
 20. The device of claim 19, wherein said plurality of accelerometers are directly connected to said electronic module for reading the recording.
 21. The device of claim 19, wherein said plurality of accelerometers are remotely connected with said electronic module for reading the recording, and wherein said remote connection uses infrared signals.
 22. A method of detecting and recording impacts along several axes of an aeronautic propeller assembly comprising: obtaining data representative of the impacts via a plurality of accelerometers integrated with a hub of the aeronautic propeller assembly; communicating said data from each of said plurality of accelerometers to an electronic module; comparing said data to predetermined levels; storing occurrences of the impacts beyond said predetermined levels in memory; and providing for reading a number of said occurrences via a memory reading device.
 23. The method of claim 22, wherein said memory reading device receives signals representative of the number of said occurrences via a direct connection.
 24. The method of claim 22, wherein said memory reading device receives signals representative of the number of said occurrences via remote transmission.
 25. The method of claim 24, wherein said remote transmission is via infrared signals. 